Dual durometer clip

ABSTRACT

A clip ( 10 ) for fastening a panel ( 50 ) to a support structure ( 52 ) is provided. The clip ( 10 ) has a plate ( 12 ) and a stem ( 14 ) extending from the plate. The stem 14 has a base ( 22 ) and a body section ( 24 ). The base ( 22 ) has a width greater than a width of the body section ( 24 ). A pair of tangs ( 16 ) extend from a distal end of the stem ( 14 ) toward the plate ( 12 ). A sealing flange ( 18 ) extends from the base ( 22 ). The sealing flange ( 18 ) is first molded from a material having a first durometer and then the plate ( 12 ), stem ( 14 ) and tangs ( 16 ) are molded from a material having a second durometer greater than the first durometer.

RELATED APPLICATION

This application claims priority to and all the benefits of U.S.Provisional Application No. 60/218,598, filed on Jul. 17, 2000.

FIELD OF INVENTION

This invention relates to a dual durometer clip. In particular, thisinvention relates to a fastener having a flange of softer material forsealing the fastener against a mounting surface.

BACKGROUND OF INVENTION

W-Clips are well know in the automotive industry to attach a cladding orpanel to a support structure. W-Clips generally have a base plate with astem extending therefrom. A pair of elastic tangs extend from the tip ofthe stem towards the base plate. A sealing flange is spaced from thebase plate and extends about the base of the stem. The sealing flangescloses the aperture on the support structure. Examples of such clips areillustrated in U.S. Pat. Nos. 5,173,026; 6,689,863; 5,704,753; and5,857,244.

The prior art W-Clips can be made as a single injection molding. Sincethe stem and base plate of the W-clip needs to be relatively rigid toprovide sufficient support for the cladding or panel, the sealing flangewill also be relatively rigid and thus provides only a limited amount ofsealing.

Alternatively, the prior art W-Clips can be manufactured using anover-molding technique. The base plate and stem are first molded using arelatively rigid material and then a softer material is over molded toform the sealing flange.

Typically, the base of the stem has the same width as the rest of thestem. If a softer flange is over-molded onto the base of the stem, theslip could be inserted beyond the flange causing the flange to distortand reduce its effectiveness as a seal.

Alternatively, a more rigid flange could be initially molded and asofter material over-molded at the outer periphery of the flange. Themore rigid flange prevents the clip from being over-inserted. However,the complexity and cost of the mold required to produce such a clipincreases dramatically.

Thus, there exist a need for a simple W-clip which provides an effectivesealing flange, which-cannot be over-installed and which is easilymolded.

SUMMARY OF INVENTION

The disadvantages of the prior art may be overcome by providing a cliphaving a stem with a base which is wider than the body of the stem. Asealing flange is first molded and then the body of the stem and baseplate is under-molded.

According to one aspect of the invention, there is provided a clip forfastening a panel to a support structure. The clip has a plate and astem extending from the plate. The stem has a base and a body section.The base has a width greater than a width of the body section. A pair oftangs extends from a distal end of the stem towards the plate. A sealingflange extends from the base of the stem. The sealing flange is firstmolded from a material having a first durometer and then the plate, stemand tangs are molded from a material having a second durometer greaterthan the first durometer.

According to another aspect of the invention, there is provided a methodof forming a clip. The method includes the steps of:

providing a mold having a cavity complementary to the clip;

moving an injector pin to close off a portion of the cavitycomplementary to the stem;

moving a sleeve surrounding the injector pin to a position to close aportion of the cavity defining the sealing flange;

injecting a first material having a first durometer into the cavity tomold the sealing flange;

retracting the injector pin and the sleeve to close the cavity at aposition to define a portion of the plate;

injecting a second material having a second durometer greater than thefirst durometer into the cavity to mold the plate, stem and tangs; and

opening the mold and ejecting the clip.

According to another aspect of the invention, there is provided anapparatus for molding a clip according to the present invention. Theapparatus has a mold having a first mold cavity complementary to thesealing flange and a second mold cavity complementary to said plate,stem and tangs. An injector pin communicates with the first and secondmold cavity and a source of first material of a first durometer and asource of second material of a second durometer. The second durometer isgreater than the first durometer. A sleeve surrounds the injector pinand slides relative thereto. The pin and sleeve each move independentlybetween a first position closing the first mold cavity and a secondposition closing the second cavity. The pin closes a portion of thesecond cavity corresponding to the stem and tangs when the pin is in thefirst position.

DESCRIPTION OF THE DRAWINGS

In drawings which illustrate the preferred embodiment of the invention,

FIG. 1 is a perspective view of the W-Clip of the present invention;

FIG. 2 is an end elevational view of the W-Clip of FIG. 1;

FIG. 3 is a side elevational view of the W-Clip of FIG. 1;

FIG. 4 is a sectional view of a mold for molding the W-Clip of FIG. 1,molding the sealing flange;

FIG. 5 is a section view of the mold of FIG. 4, molding the base portionof the W-Clip of FIG. 1; and

FIG. 6 is a side sectional view of the W-Clip of Figure fastening aplastic panel to a support structure.

DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-3, a W-Clip 10 of the present invention. The clip10 generally comprises a plate 12, a stem 14, a pair of tangs 16 and asealing flange 18.

Plate 12 is illustrated as rectangular with tabs 20 extending fromopposite end regions of the plate 12. Size and shaping of the plate 12and the position and size of the tabs 20 are dictated by the particularapplication of the clip 10.

Stem 14 extends generally perpendicularly from the plate 12. Stem 14 hasa base 22 and a body section 24. As is apparent in FIG. 2, the base 22has a greater width than the body section 24. Base 22 has a thicknessslightly greater than the thickness of the plate 12. Body section 24preferably has a tapered end.

A pair of resilient tangs 16 extend from the tapered end of the bodysection 24 towards the plate 12. The tangs 16 each have a notch 26 atthe distal ends thereof. The notches 26 align with the base section 24of the stem 14.

Sealing flange 18 extends radially outwardly from the base 22. Thesealing flange 18 presents a concave seal.

Referring to FIGS. 4 and 5, a mold 30 for manufacturing the clip 10 isillustrated. The mold 30 comprises mold portions 32 and 34 and mirrormage mold portions (not illustrated). Optionally mold halves could beutilized. Mold portion 32 has a cavity 36 which is complementary to thebody section 24 and tangs 16. Additionally, the surface 38 surroundingthe entrance of cavity 36 is contoured to be complementary to theconcave surface of the sealing flange 18.

Mold portion 34 has a cavity 40 complementary to the plate 12, the base22 and the convex side of sealing flange 18. Mold portion 34 has a bore42 which communicates with cavity 40. Optionally, mold portions 32, 34can be made as a single mold half with a mirror image mold half. Theparting line of the clip 10 is longitudinally of the base 12.

To mold a clip 10, the mold 30 is closed. An injector pin 44 has asleeve 46. The pin 44 and sleeve 46 is inserted through bore 42 untilpin 44 abuts with surface 38 and closes off cavity 36. Sleeve 46 isaligned with the inner edge of the mold cavity 40 defining plate 12. Afirst relatively softer or low durometer material, such as a syntheticrubber, ZYTEL FN or SANTOPRENE is injected into the cavity 40surrounding the pin forming sealing flange 18. The injector pin 44 andsleeve 46 are retracted to the outer edge of cavity 40. A secondrelatively rigid or high durometer material, such a NYLON is injectedinto cavity 36 and the remainder of cavity 40 to form the plate 12, thestem 14 and the tangs 16. The mold 30 is opened and the clip 10 isejected.

Referring to FIG. 6, a clip 10 is illustrated fastening a plastic panel50 to a support structure 52. The plastic panel 50 has an aperture sizedto receive the base 22 of stem 14 and the support structure 52 has anaperture smaller than the diameter of the aperture of the plastic panel50. The width of the base 22 prevents the clip 10 from being insertedinto the support structure 52. The tangs 16 are biased and sized toenable insertion of the stem 14 through the aperture of supportstructure 52 until the tangs 16 snap into place when fully inserted. Thebias of tangs 16 retain the tangs 16 in engagement with the back side ofthe support structure 52, i.e., the notches 26 prevent removal of theclip 10 from the support structure 52.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation. Manymodifications and variations of the present invention are possible inlight of the above teachings. It is, therefore, to be understood thatwithin the scope of the appended claims the invention may be practicedotherwise than as specifically described.

1. A method of forming a clip having a plate, a stem extending from saidplate, a pair of tangs extending from a distal end of the stem towardssaid plate, and a sealing flange extending from said body section ofsaid stem adjacent said base, said stem having a base and a bodysection, said base having a width greater than a width of said bodysection, said method comprising steps of: providing a mold having acavity complementary to said clip, moving an injector pin to close off aportion of the cavity complementary to said stem, moving a sleevesurrounding said injector pin to a position to close a portion of thecavity defining said sealing flange, injecting a first material having afirst durometer into said cavity to mold said sealing flange, retractingsaid injector pin and said sleeve to close said cavity at a position todefine a portion of said plate; injecting a second material having asecond durometer into said cavity to mold said plate, stem and tangs;opening said mold and ejecting said clip.
 2. A method as claimed inclaim 1 wherein said first material having a first durometer is asynthetic rubber and said second material having a second durometer isnylon.
 3. An apparatus for molding a clip wherein the clip includes aplate, a stem extending from the plate, a pair of tangs extending from adistal end of the stem towards the plate, and a sealing flange extendingfrom the stem, said apparatus comprising: a mold having a first moldcavity complementary to said sealing flange and a second mold cavitycomplementary to said plate, stem and tangs, an injector pincommunicating with said first and second mold cavity and a source offirst material of a first durometer and a source of second material of asecond durometer, said second durometer being greater than said firstdurometer, and a sleeve surrounding said injector pin and slidablerelative thereto, said pin and sleeve each moveable between a firstposition closing said first mold cavity and a second position closingsaid second cavity.
 4. An apparatus as claimed in claim 3 wherein saidpin closes a portion of the second cavity corresponding to said stem andtangs when said pin is in said first position.
 5. An apparatus asclaimed in claim 4 wherein said first and second mold cavities have acommon volume.